1. Field of the Invention
The present invention relates to an air conditioning apparatus for a vehicle, which employs a flammable refrigerant.
2. Description of Related Art
An air conditioning apparatus for a vehicle, employing a flammable refrigerant of propane gas or the like, has been proposed recently in view of the tendency of non-Freon refrigerant for an air conditioning apparatus.
There has been also proposed a device for preventing leakage of refrigerant of an air conditioning apparatus for a vehicle employing a flammable refrigerant as disclosed in JP-U-58-54904 for example. More specifically, a gas sensor for detecting leakage of refrigerant is provided within a passenger compartment (cabin) or within the air conditioning apparatus for a vehicle. Accordingly, refrigerant leakage is monitored constantly (including time period during which the engine stops such as when the vehicle is parked), and when leakage of refrigerant has been detected, an inside/outside air switching door is set in an outside air introduction state and a rotation direction of a blower is reversed, and an air-mix door is set in a maximum cooling state, so that leaked refrigerant is discharged outside the vehicle.
On the other hand, an evaporator, a heater core, the air-mix door, and the like are disposed in an air passage of the air conditioning apparatus for a vehicle, and therefore passage resistance (pressure loss) is large, and a sufficient amount of blown air cannot be assured with an axial-flow fan. Accordingly, a scirocco fan is generally employed as the fan for a blower to keep its compactness while assuring a sufficient amount of blown air.
For this reason, in the blower of an air conditioning apparatus for a vehicle, as characteristics of the scirocco fan generally relates to the shape of the scroll casing, the direction of blown air is not reversed even when the scirocco fan is reversely rotated.
Consequently, according to the above device in which the blower is reversely rotated, the leaked refrigerant cannot be certainly discharged outside the vehicle. Therefore, there may be a problem that the passenger compartment is filled with the refrigerant while the air conditioning apparatus is stopped and the passenger is absent, such as when the vehicle is parked.